Abrasive-impregnated cutting structure having anisotropic wear resistance and drag bit including same

Abstract

An abrasive-impregnated cutting structure for use in drilling a subterranean formation is disclosed. The abrasive-impregnated cutting structure may comprise a plurality of abrasive particles dispersed within a substantially continuous matrix, wherein the abrasive-impregnated cutting structure exhibits an anisotropic wear resistance. One or more of the amount, average size, composition, properties, shape, quality, strength, and concentration of the abrasive particles may vary within the abrasive-impregnated cutting structure. Anisotropic wear resistance may relate to a selected direction, such as, for example, one or more of an expected direction of engagement of the abrasive-impregnated cutting structure with the subterranean formation and an anticipated wear direction. Anisotropic wear resistance of an abrasive-impregnated cutting structure may be configured for forming or retaining a formation-engaging leading edge thereof. A rotary drag bit including at least one abrasive-impregnated cutting structure is disclosed.

1. An abrasive-impregnated cutting structure for use on a rotary drag bit for drilling a subterranean formation, comprising:
 a plurality of abrasive particles dispersed within a body comprising a substantially continuous matrix, the plurality of abrasive particles being at least one of configured and arranged within the substantially continuous matrix to vary in at least one physical characteristic in proportion to a distance from a first location within the body with respect to at least one direction therethrough; 
 wherein the abrasive-impregnated cutting structure exhibits an anisotropic wear resistance. 
 
   
   
     2. The abrasive-impregnated cutting structure of  claim 1 , wherein:
 the plurality of abrasive particles comprise at least one of natural diamond, synthetic diamond, tungsten carbide, silicon nitride, cubic boron nitride, and silicon carbide; and 
 the substantially continuous matrix comprises at least one of copper, a copper-based alloy, nickel, a nickel-based alloy, cobalt, a cobalt-based alloy, iron, an iron-based alloy, silver, and a silver-based alloy. 
 
   
   
     3. The abrasive-impregnated cutting structure of  claim 1 , wherein the plurality of abrasive particles are distributed non-uniformly within the substantially continuous matrix. 
   
   
     4. The abrasive-impregnated cutting structure of  claim 1 , wherein the abrasive-impregnated cutting structure comprises a discrete cutting structure. 
   
   
     5. The abrasive-impregnated cutting structure of  claim 1 , wherein the abrasive-impregnated cutting structure comprises a segment. 
   
   
     6. The abrasive-impregnated cutting structure of  claim 1 , wherein the plurality of abrasive particles vary with respect to one or more of an average size, concentration, properties, orientation, strength, composition, and shape. 
   
   
     7. The abrasive-impregnated cutting structure of  claim 1 , wherein the anisotropic wear resistance is configured for preferentially self-sharpening the abrasive-impregnated cutting structure. 
   
   
     8. The abrasive-impregnated cutting structure of  claim 1 , wherein an inherent quality of the plurality of abrasive particles related to wear resistance thereof respectively, varies within the abrasive-impregnated cutting structure. 
   
   
     9. The abrasive-impregnated cutting structure of  claim 1 , wherein the anisotropic wear resistance relates to an expected direction of engagement of the abrasive-impregnated cutting structure with the subterranean formation. 
   
   
     10. The abrasive-impregnated cutting structure of  claim 9 ,
 wherein the abrasive-impregnated cutting structure is configured for at least one of forming and retaining a formation-engaging leading edge thereof in response to cutting engagement thereof with the subterranean formation. 
 
   
   
     11. The abrasive-impregnated cutting structure of  claim 10 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure is configured for producing, in response to cutting engagement thereof with the subterranean formation, a selected amount of clearance. 
   
   
     12. The abrasive-impregnated cutting structure of  claim 9 , wherein the anisotropic wear resistance relates to an anticipated wear direction. 
   
   
     13. The abrasive-impregnated cutting structure of  claim 12 , wherein the anticipated wear direction is substantially perpendicular to the expected direction of engagement with the subterranean formation. 
   
   
     14. The abrasive-impregnated cutting structure of  claim 12 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure is configured to decrease from a formation-engaging leading edge thereof in the expected direction of engagement with the subterranean formation. 
   
   
     15. The abrasive-impregnated cutting structure of  claim 1 , wherein the anisotropic wear resistance relates to an anticipated wear direction. 
   
   
     16. The abrasive-impregnated cutting structure of  claim 15 , wherein the plurality of abrasive particles are at least one of configured and arranged to provide the anisotropic wear resistance with respect to an expected direction of engagement with the subterranean formation. 
   
   
     17. The abrasive-impregnated cutting structure of  claim 16 , wherein the anticipated wear direction is substantially perpendicular to the expected direction of engagement with the subterranean formation. 
   
   
     18. The abrasive-impregnated cutting structure of  claim 16 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure decreases from a formation engaging leading edge in the expected direction of engagement with the subterranean formation. 
   
   
     19. The abrasive-impregnated cutting structure of  claim 16 , wherein
 the anisotropic wear resistance is configured to preferentially self-sharpen the abrasive-impregnated cutting structure. 
 
   
   
     20. The abrasive-impregnated cutting structure of  claim 16 , wherein the abrasive-impregnated cutting structure is configured for at least one of forming and retaining a formation engaging leading edge in response to cutting engagement thereof with the subterranean formation. 
   
   
     21. The abrasive-impregnated cutting structure of  claim 20 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure is configured for producing, in response to cutting engagement thereof with the subterranean formation, a selected amount of clearance. 
   
   
     22. The abrasive-impregnated cutting structure of  claim 15 , wherein an inherent quality of the plurality of abrasive particles related to wear resistance thereof varies, respectively, within the abrasive-impregnated cutting structure. 
   
   
     23. The abrasive-impregnated cutting structure of  claim 1 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure varies in proportion to a radial distance from a longitudinal axis of a rotary drag bit bearing the abrasive impregnated cutting structure. 
   
   
     24. The abrasive-impregnated cutting structure of  claim 23 , wherein one or more of an average size, concentration, properties, orientation, strength, composition, shape, and an inherent quality related to wear resistance of the plurality of abrasive particles varies in proportion to the radial distance from the longitudinal axis of the rotary drag bit. 
   
   
     25. The abrasive-impregnated cutting structure of  claim 23 , wherein the anisotropic wear resistance of the abrasive-impregnated cutting structure increases substantially in proportion to the square of a radial distance thereof from the longitudinal axis of the rotary drag bit. 
   
   
     26. A rotary drag bit for drilling a subterranean formation, comprising:
 a bit body having a face for drilling the subterranean formation, the face extending from a longitudinal axis of the rotary drag bit to a gage thereof; and 
 at least one abrasive-impregnated cutting structure disposed on the face of the bit body, the at least one abrasive-impregnated cutting structure comprising a plurality of abrasive particles dispersed within a body comprising a substantially continuous matrix, the plurality of abrasive particles being at least one of configured and arranged within the substantially continuous matrix to vary in at least one physical characteristic in proportion to a distance from a first location within the body with respect to at least one direction therethrough; 
 wherein the at least one abrasive-impregnated cutting structure exhibits an anisotropic wear resistance. 
 
   
   
     27. The rotary drag bit of  claim 26 , wherein:
 the plurality of abrasive particles comprise at least one of natural diamond, synthetic diamond, tungsten carbide, silicon nitride, cubic boron nitride, and silicon carbide; and 
 the substantially continuous matrix comprises at least one of copper, a copper-based alloy, nickel, a nickel-based alloy, cobalt, a cobalt-based alloy, iron, an iron-based alloy, silver, and a silver-based alloy. 
 
   
   
     28. The rotary drag bit of  claim 26 , further comprising:
 a plurality of blades extending generally radially upon the face of the rotary drag bit; 
 wherein the at least one abrasive-impregnated cutting structure comprises at least a portion of at least one of the plurality of blades. 
 
   
   
     29. The rotary drag bit of  claim 26 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure varies in proportion to a radial distance from a longitudinal axis of a rotary drag bit. 
   
   
     30. The rotary drag bit of  claim 29 , wherein one or more of an average size, concentration, properties, orientation, strength, composition, shape, and an inherent quality related to wear resistance of the plurality of abrasive particles of the at least one abrasive-impregnated cutting structure varies in proportion to the radial distance from the longitudinal axis of the rotary drag bit. 
   
   
     31. The rotary drag bit of  claim 29 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure increases substantially in proportion to a square of the radial distance thereof from the longitudinal axis of the rotary drag bit. 
   
   
     32. The rotary drag bit of  claim 26 , wherein the anisotropic wear resistance is configured for preferentially self-sharpening the at least one abrasive-impregnated cutting structure. 
   
   
     33. The rotary drag bit of  claim 26 , wherein an inherent quality of the plurality of abrasive particles related to wear resistance thereof varies, respectively, within the at least one abrasive-impregnated cutting structure. 
   
   
     34. The rotary drag bit of  claim 26 , wherein an inherent quality related to wear resistance of the at least one abrasive-impregnated cutting structure increases substantially in proportion to the square of a radial distance thereof from the longitudinal axis. 
   
   
     35. The rotary drag bit of  claim 26 , wherein the at least one abrasive-impregnated cutting structure is integral with the bit body. 
   
   
     36. The rotary drag bit of  claim 26 , wherein the at least one abrasive-impregnated cutting structure is secured to the bit body by a brazing compound. 
   
   
     37. The rotary drag bit of  claim 26 , wherein the anisotropic wear resistance relates to an expected direction of engagement of the at least one abrasive-impregnated cutting structure with the subterranean formation. 
   
   
     38. The rotary drag bit of  claim 37 ,
 wherein the at least one abrasive-impregnated cutting structure is configured for at least one of forming and retaining a formation-engaging leading edge thereof in response to cutting engagement with the subterranean formation. 
 
   
   
     39. The rotary drag bit of  claim 38 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure is configured for producing, in response to cutting engagement with the subterranean formation, a selected amount of clearance between a surface of the at least one abrasive-impregnated cutting structure and the subterranean formation. 
   
   
     40. The rotary drag bit of  claim 37 , wherein the anisotropic wear resistance relates to an anticipated wear direction. 
   
   
     41. The rotary drag bit of  claim 40 , wherein the anticipated wear direction is substantially perpendicular to the expected direction of engagement with the subterranean formation. 
   
   
     42. The rotary drag bit of  claim 40 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure is configured to decrease from a formation-engaging leading edge thereof in the expected direction of engagement with the subterranean formation. 
   
   
     43. The rotary drag bit of  claim 26 , wherein the anisotropic wear resistance relates to an anticipated wear direction. 
   
   
     44. The rotary drag bit of  claim 43 , wherein the plurality of abrasive particles are at least one of configured and arranged to provide the anisotropic wear resistance with respect to an expected direction of engagement with the subterranean formation. 
   
   
     45. The rotary drag bit of  claim 44 , wherein the anticipated wear direction is substantially perpendicular to the expected direction of engagement with the subterranean formation. 
   
   
     46. The rotary drag bit of  claim 44 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure decreases from a formation-engaging leading edge thereof in the expected direction of engagement with the subterranean formation. 
   
   
     47. The rotary drag bit of  claim 44 , wherein the anisotropic wear resistance is configured to preferentially self-sharpen the at least one abrasive-impregnated cutting structure. 
   
   
     48. The rotary drag bit of  claim 44 , wherein the at least one abrasive-impregnated cutting structure is configured for at least one of forming and retaining a formation-engaging leading edge in response to cutting engagement with the subterranean formation. 
   
   
     49. The rotary drag bit of  claim 48 , wherein the anisotropic wear resistance of the at least one abrasive-impregnated cutting structure is configured for producing, in response to cutting engagement with the subterranean formation, a selected amount of clearance. 
   
   
     50. The rotary drag bit of  claim 43 , wherein an inherent quality of the plurality of abrasive particles related to wear resistance thereof varies, respectively, within the at least one abrasive-impregnated cutting structure.